Electric switch



Jan. l5 1924.

H. G. FRENCH ET AL- ELECTRIC swl'rm Filed Oct. 10

L., wu ...n m smufo maw.. u T?. A en J mgm e Ir HHb Patented Jan. l5, 1924.

UNITED STATES PATENT OFFICE.

HENRY G. FRENCH AND HERMAN J'. H. HUBER, OF SCHENECTAYDY, NEW YORK, AS- SIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC SWITCH.

Application filed October 10, 1922.. Serial No. 593,606.

To all y11i/0m it may concern:

Bc it known that we, HnN-RY (i. FRENCH and HERMAN J. H. Homan, citizens of the United States, residin f at Schenectady, county ot Schenectady, tate of New York, have invented certain new and useful Im provements in Electric Switches, of which the following is a specification.

Our invention relates to electric switches and more particularly to contact devices of the relatively movable cooperating type and has for an object to provide an improved contact device of such flexibility and con-- struction as to insure that the relatively movable contacts register correctly for a surface to surface contact of maximum eticiency irrespective of niceties in alignment of the parts supporting the contacts.

Our invention will be better understood from the following description taken 1n connection with the accompanying drawing and its scope will be pointediout in the appended claims.

Fig. 1 is an elevation, with parts broken away, illustrating an embodiment of our invention, the ,suporting members of the relatively movable contacts being shown in alignment, F ig. .2 is an elevation similar to Fig. 1 but showing the supporting members of the contacts out of, alignment, Fig. 3 is a plan, with parts broken away, of the embodiment ofthe invention-shown .in Figs, 1 and 2, and Fig. 4 illustrates an application of the embodiment of the invention shown in Figs` 1,2 and 3 to a switch structure of the removable truck panel type vshown n elevation.

In switch-gear embodying relatively movable cooperating contacts it is frequently diiicult andoten impractical to employ the refinements of construction and adjustments necessary to a precise alignmentof the contact supporting structures so as to ensure that the contacts'will register with that nicety essential to a. highly eficient electric contact. Eventhough tlierei'inements .of construction and adjustments are carried to an extreme, the complex structure ofmodern switchgear, the inevitable 'wear of the parts, shocks and jars .of operation which disturb the adjustments,'and other ,causes malreit very troublesome anddiicult particularly in contact devcesof the plug and socket type and especially when heavy currents have' to'be carried to obtain an efiicient surface to surface contact principally because of variations and inaccuracies in the alignment of the contact supporting structures. rentiou, we provide an improved construction of contacts which obviates this diiiculty and renders unnecessary the refinements ot' construction requisite to a precise aiignment of the Contact supporting structures and therefore provides a more economical and efficient construction which is capable of withstanding relatively hard use.

In the figures of the accompanying drawing, We have illustrated an embodiment of our invention in an electric switching or dis connecting device of the plug and socket type comprising relatively movable cooperating contacts, one of which may be fixed. The fixed contact member is shown as the socket part of the switching device and may comprise .a portion or terminal 1 which, for pur poses of illustration, may be ,secured by a clamping member .2 and bolts 3 to a bus bar structure comprising spaced `bus bars 4 separated by spacers' 5, the bus bar Structure being supported by insulators 6 secured to any suitable supporting means or framework 7, see Fig. 4. Theterminal 1 is provided With a plurality of spaced jaws `or contact members 8, the ends ofivhicb are preferably curved .outward to form a flaring passage way .or mouth in order better Lto =re ceive and guide the engaging parts ofthe cooperating contact.

Our invention particularly resides in the contact device which constitutes the plug part of the electric switching device and is herein shown as the cooperating movable Contact. The contact device comprises a terminal member 9 which may be provided with a conducting stud or ,shank 10 shown as extending through an insulator 11 which may be secured to a movable structure such as a truck 12, see Fig. 4, or if used in circuit breaker construction, the contact device may be mounted in a manner well known to the art. Pivotally associated with the terminal 9 on oppositesides thereof on pivot pins 13 are supporting ,members such as plates 14 which serve to support or carry the parts of the contact device which cooperate with and engage the jaws 8 of the fixed contact. Mounted on the plates 14 and extending transversely thereof is a supporting member According to our in- 4 Sil such as a rod or pin 15 on which is mounted between the plates 14, a lever or equalizing bar 16. l

In order to provide a rigid assembly of the plates 14 so that the plates cannot twist or move relatively to each other and to hold the bar 16 in place, the rod 15 may be provided with spacers such as sleeves 17 hetween the plates 14 and the bar 16 and may also have its ends threaded to receive nuts 18 for rigidly clamping the assembly, the ends of the rod 15 being spun over the nuts 1S to prevent them from working loose, or the nuts otherwise secured in any suitable manner. ln order that the plates 14 may normally be held in alignment with the terminal 9, as for example when the cooperating' cont-acts are not in engagement, suit- ;ihlc resilient means is provided such as compression springs 19 mounted between the terminal 9 and the bar 16 and arranged to exert. forces on the bar 16 adjacent the ends thereof tending to align the plates 14 with the terminal 9. For centering and maintaining the springs 19 in'position, the equalizing bar 16 may be provided with suitable projections or lugs 20. The spriiigs 19, the equalizing bar 16 and the shaft 15 therefore tend to maintain the plates 14 in alignment with the terminal 9 and also allow movement of the plates 14 relatively to the ter-v minal 9. Loosely lnounted `on the plates 14 so as to be movable `relatively thereto and independently of each other are contact members or fingers 21 which are adapted to engage the jaws 8 of the 'terminal 1. The nose or outer end of the contact fingers is curved inwardly in order to guide the contact fingers into engagement with the flaring mouth of the'jaws 8 and to ensure the regis ter of the contact fingers with the jaws'S when the supporting structures of the relatively movable contacts are not in alignment :is shown in Fig. '2. Each of the contact fingers 21 may comprise a single member providing the necessary contact area or a plurality of narrow contact fingers arranged in sets, as is more clearly shown in Fig. 3, the latter arrangement being preferable as it provides a more flexible structure and therefore insures a better electric Contact. The contact. fingers 21 may be connected to the terminal 9 by any suitable conducting means such as fiexible connectors or leads 22 which may be secured to the terminal 9 in any suitable manner such as by plates 23 and bolts 24 and riveted, brazed or otherwise secured to the Contact fingers 21.

lVith this arrangement the outer bolts 24 may be used to lock the pivot pins 13 from turning, the Shanks of the bolts interlocking for example with the concave inner ends of the pivot pins 13 whichl are screwed into the terminal 9. For loosely mounting the contact fingers 21 on .the plates 14, the fingers may he provided with supporting members or brackets 25 and may be supported be tween the plates 14 by spaced pins 26 extending through the brackets 25 between the plates 14 and through slots 27 therein which permit movement of the pins 26 and there fore of the contact fingers 21 independently of each other and of the plates 14. Each contact finger or set of contact fingers is preferably supported on at least two of the pins 26. Suitable resilient means, such as compression springs 28, are mounted between the Contact fingers 21 and internic diate the pins 26 supporting each contact finger or set of fingers to spread the contact` fingers apart and when the contacts are not in engagement, the contact. fingers are moved to their limit of travel which is determined by the pins 26 coming to rest against the outer ends of their respective slots. The springs 28 may be centered and maintained in position by suitable means such as lugs 29 on the brackets 25. The spacing of the slots and the length thereof is such that the contact fingers 21 may .be spaced apart a distance relatively greater than the distanceV between the contact jaws 8 in order that upon engagement of the Contact fingers 21 with the jaws 8, the fingers may be readily defiected' by the jaws and also that there may be a substantial pressure between the engaging parts of the cooperating contacts. It is therefore obvious that the construction is such that the compression springs 28 can be made bo exert a very considerable presA sure against the contact fingers 21 so as to insure a firm and positive Contact with the jaws 8. y

VVith-this construction and arrangement of parts, it is obvious thatif rthe supports of the cooperating contacts are in alignment as shown'in Fig. 1 the springs 19 will hold the plates 14fi'nv alignment with the terminal 9 and 'the contact fingers 21 will enter the fiared jaws 8 and be forced together against the pressure of the springs 2S so as to insure a good surface to surface contact. If, how,- ever, the Contact supporting structures are not in alignment as shown in iig. 2` the contact fingers 21 will engage the jaws S at an angle andwill therefore be canted into alignment with the jaws 8 so as to register therewith for a surface to surface contact since the lost motion mounting of the contact fingers 21 permits them to rock freely relatively to the plates 14. At the same time assuming the Contact supports considerably out of alignment, two diagonally opposite pins 26, the upper left and lower right hand pins as shown in Fig. 2, reach the limit of travel in their respective slots and the plates 14 will be turned upwardly as shown in Fig. 2 against the action of the springs 19. Each of the contact fingers 21 is thus maintained free to rock or turn about a single point,

that is one of its supporting pins 26 and the Contact finger is therefore, under `the action of springs 28, maintained in surface to surface contact with its cooperating jaws 8. iVhen the contacts are separated or disengaged the springs 19 acting on the equalizing bar 16 turn the plates 14 into alignment with the terminal 9 and the springs A28 spread the contact fin ers 21 apart until the pins 26 bear against tlrie outer ends of their respective slots.

In F ig. 4 we have illustrated va switch gear structure to which our invention is particularly adapted. This structure is known to the art as the removable truck panel type and comprises a housing or cubicle 3() and a truck 12 arranged to be rolled into and out of the housing 30. Mounted in the housing 30 at the rear thereof `and on a supporting fram-e 7 are the distributing bus bars 4 mounted on insulators 6 and having terminals 1 with jaws 8 comprising the tixed contac't as shown in Figs. 1 and 2. 'The particular arrangement sho-wn is for a three phase alternating current system. Similar lXcd contacts 8 are mounted in a row within the housing 80 beneath the bus bars 4 and to these contacts are connected incoming leads 31. Mounted on the rear of the truck structure are insulators -10 supporting cointact devices embodying our inventionas shown in Figs. 1, 2 and '3. As the truck 12 is moved into the housingt), the Contact devices 9 thereon engage the fixed contacts 8, 8. The fixed contacts 8, 8 are preferA ably made the live contacts, because'of their extreme simplicity of' construction and therefore slight probability of getting out of order. The contacts 9 embodying o-ur invention are of more complex structure, and by making them the movablecontacts` Athey are dead when the truck 1Q is removed and are therefore conveniently afndfsaifely accessible for inspection and repairs. The truck has mounted thereon a suitable circuit breaker 32 arranged to be controlled by an operating mechanism 33 to complete a circuit from the movable contacts 9 connected to the fixe-d contacts 8 of the incoming leads 31 to the distribution bus bars 4 by means of suitable leads 34. Suitable auxiliary devices for operating relays, measuring and indicating instruments, etc., which may be mounted on the truck panel. such as current and potential transformers 35 and 36 respectively are also mounted on the truck.

With switch gear structure of the type illustrated in Fig. 4, it will be obvious that if the disconnecting or contact devices are of such construction as to necessitate a precise alignment of the contact supporting structures, an inordinate amount of time and labor is necessary to acomplish the requisite refinements of adjustment. Moreover, as

the truck panels are generally made interchangeable and as it is frequently desirable to provide spaces, slight variations in the adjustments of the mountings increase the diiticul'ty. Also dirt or other foreign matter either on or under the truck wheels results in misalignment of the contact supporting structures. Furthermore the switch gear is subject to a certain amount of more or less vhard use in operation and this tends to disturb any refinements in adjustment. By the use of contact devices embodying our invention however the necessity ofsuch nicety of adjustment of the contact supporting structures is eliminated as the flexible construction of the contact device 9 permits considerable leeway with re spect to the alignment of the Contact supporting structures. This reduces cost and simpliiies operation and ensures that the cooperating contacts will register with that surface to `surface engagement which is requisite Vto an etiicient electric contact. In the arrangement shown, the contact device 9 eliminates dii'iiculties due to 'the contact supporting structures being vertically out of alignment` In order to provide foriateral or side play of the truok 12, thaitis` to say when the Contact supporting 'structures are out of `aligmnent horizontally, the jaws 8 of the'fixedcontac-t may be made wider than .the Contact fingers 21, that is to say the Widthof the movable Contact.

What we claim afs new and desire to secure by Letters Patent of the United States` ifs,-`

1. A Contact devicetcomprisinga terminal member,"supporting members 'piivottally associated therewith, resilient means for `nofrmally` maintaining said supporting members in alignment with' said terminal member and arrangedvto allow movement of said supporting membersrelatively to the terminal member, a plurality of Contact fingers loosely mountedon said supporting members and independently movable relatively thereto, `and resilient means arranged to spread said' fingers apart.

2. A contact device comprising a terminar, supporting members pivotally associated therewith, an equalizing member supported by said supporting members, resilient means affecting said equalizing member normally to maintain said supporting members in alignment with said terminal and arranged to allow movement of said supporting members relatively to said terminal, contact fingers carried by said supporting members an independently movable relatively thereto.` and resilient means arranged to spread said fingers apart.

3. A contact device comprising aterminal. two plates pivotally associated with said terminal on opposite sides thereof, an equalizing bar mounted between said plates and supported thereby` resilient means exerting l terminal on opposite sides thereof, an equalizing bar mounted between said plates and. supported thereby, resilient means mounted between said bar and said terminal arranged to exert forces on said bar tending to maintain said plates in alignment with the terminal and adapted to `allow movement of saidplates relatively to the terminal, a pair of Contact fingers loosely mounted on and supported by said plates for move ment relatively thereto independently of each other, fiexible conducting means oonneeting said fingers to said terminal, and resilient means arranged to spread said oontact fingers apart. t

5. A Contact devieeeomprisingaterminal, two plates pivotally associated with said terminal on opposite sides thereof, an equalizing bar mounted between said platesand supported thereby, resilient means mounted between said bar and said terminal arranged to exert forces on said bar tending to maintain said plates in alignment with the terminal and adapted to allow movement of said plates relatively to the terminal, a plurality of Contact ngers arranged in two sets loosely' mounted on and supported by said plates for movement relatively thereto independently of each other, flexible conducting means connecting said fingers to said terminal, and resilient means arranged to spread said sets of Contact fingers apart.

G. A Contact device eomprisingaterminal,

two plates pivotally associated with said terminal on opposite sides thereof, an equalizing bar mounted between said plates and` supported thereby, resilient means mounted between said bar and said terminal arranged to exert forces on said bar tending to maintain said plates in alignment with the terminal and adapted to allow movement of said plates relatively to the terminal, a plurality of pins extending between said plates and through spaced slots therein, a pair of Contact fingers eaeh supported by at least two of said pins, resilient means betweel4 said Contact fingers arranged to spread the same apart and flexible eomlmfting means connecting said fingers to said terminal1 the construction and arrangement of parts being such that each of said lingers is adapted to be moved independently of the other and of said plates.

7. An electric switching device comprising a Contact member having two jaws and a cooperatin Contact member movable relatively to said first Contact member comprising a terminal, two plates pivotally associated with said terminal on opposite sides thereof, an equalizing bar mounted between said plates and supported thereby, resilient means exerting forces on the ends of said bar tending to maintain said plates in alignment with said terminal and arranged to allow movement of said plates relatively to the terminal, a pair of Contact fingers loosely mounted on said plates for movement relatively thereto independently of each other, and resilient means tending to spread said Contact fingers apart, whereby upon movement of one of said Contact members into engagement with the other, fsaid Contact lingers will register with said jaws irrespective of the alignment of said jaws and said terminal.

In witness whereof, we have hereunto set our hands this 9th day of October, 1922.

HENRY G. FRENCH. HERMAN J. H. HUBER. 

